The invention relates to the field of ESD cells, in particular to an ESD cell having a pinched resistive area.
FIG. 1 is a cross-sectional view of a conventional bipolar transistor-based ESD protection structure 10. Conventional bipolar transistor-based ESD protection structure 10 includes a P-type substrate 12, an N-type collector region 14, a P-type base region 16 (e.g., a P-type Si—Ge base region) and an N-type polysilicon emitter 18. The conventional bipolar transistor-based ESD protection structure 10 also includes electrical isolation regions 20 and 22. A metal base contact 24 makes contact with the P-type base region 16 via polysilicon line 26. A metal emitter contact 28 is in contact with the N-type polysilicon emitter 18, while a metal collector contact 30 is in contact with the N-type collector region 14. The metal base contact 24, the metal emitter contact 28 and the metal collector contact 30 each extends through dielectric layer 32.
Electrical schematics illustrating this conventional bipolar transistor-based ESD protection structure 10 arranged in a grounded base bipolar transistor-based ESD protection device and a Zener Triggered bipolar transistor-based ESD protection device are provided in FIGS. 2A and 2B, respectively.